Aircraft engine



May 23, 1944.

A. SCOTT AIRCRAFT ENGINE Filed April 9. 1941 ATTQIN EYB May 23, 1944, A. sco'r'r AIRCRAFT ENGINE Filed Aprii 9, 1941 3 Sheets-Sheet 2 14@ Andrew Saggi. Z5? E* n ATTORN EYS May 2,3, 1944. A. sco'rr 2,349,383

' AIRcRAF'r ENGINE Filed April 9, 1941 s sheets-sheet s Patented May 23, 1944 UNITED STATES PATENT` OFFICE` AIRCRAFT ENGINE Andrew Scott, Gary, Ind.

Application April 9, 1941, Serial No. 387,738

(Cl. A123-188) 3 Claims.

My invention relates to internal combustion engines, and has among its objects and advantages the provision of an improved aircraft engine.

An object of my invention is to provide an engine of the type described wherein a novel valve structure is incorporated and designed soA as to facilitate assembly and removal of the parts, with the structure embodying an element of simplification and relatively few parts. y

A further object is to provide an engine embodying a series of camshafts together with a novel drive for the camshafts.

Another object is to provide an engine embodying a novel construction and arrangement of rocker arms and connecting rods with the engine designed with a view to securing effective balance, high speed with resultant power gain.

In the accompanying drawings:

Figure 1 is a sectional view of the engine in accordance with my invention, with the plane of the section substantially corresponding to the axis of the crankshaft but with the latter illustrated in elevation;

Figure 2 is a sectional view along the line 2--2 of Figure 1; y

Figure 3 is a sectional view along the line 3-3 of Figure 1;

Figure 4 is a sectional view along the line 4-4 of Figure 2; and

Figure 5 is a sectional view along the of Figure 4.

In the embodiment selected to illustrate my invention, I make use of a crank case I having an end plate I2 bolted to one end thereof, which end plate is provided with a boss I4 bored to receive a bearing bushing I6 which supports the bearing pin I8 of the crankshaft 20. Pin I8 is extended at 22 for connection with the propeller, and a seal 24 abuts the outer ends of the bushing I6 and the boss I4 and is held thereagainst by reason of a retainer 26 secured to the boss by bolts 28.

The opposite end of the crank case I0 is provided with a wall 30 and an annular flange 32 having edge to edge engagement with the flange 34 of a cover plate 36. Bolts 38 xedly secure the two flanges 32 and 34 and these flanges cooperate with the wall 30 and the plate 38 to proline -5 vide a chamber 40 in which the driving means for the camshafts are located. y

The second pin 42 of the crankshaft is supported by a bearing 44 held in the annular ange 46 by a retainer 48 bolted at 50 to the wall 30. P11142 is fashioned integrally with the crank arm 52 and the latter is bored at`54 to receive the short shaft-,5G at one end of the crankpin l58. A key secures the arm 52 to the shaft 56 and the two parts are additionally secured by means of a bolt 62 intersecting the peripheries of the shaft 56 and the bore 54. The arm 52 is split, as at 64 in Fig. 3, so that tightening ofthe bolt B2 additionally secures the arm 52 to the shaft. The second crank arm 66 to which the pin I8 is se-` cured is formed integrally with the crankpin 58.`

Spaced circumferentially of the crank case Ill are ve cylinders 68, 10, 12, 14 and 16. In ac` cordance with Figs. 1 and 3, the cylinderl has a flange 'I8 tted against the face 80 of the boss 82 on the crank case I0. This boss is-boredat 84 f or the reception of the inner end of ther cylinder and the ange 18 is made secure to the crank case by bolts 86. All the cylinders are identical in construction, so that the description of one will apply to all. Each cylinder is 'also provided with heat dissipating ns 88.

The pistons of the cylinders 68 through 16 are connected with the crankpin 58 by connecting rods 92, 94, 96, 98 and |00, respectively. AThe connecting rods 92 through |00 are respectively provided with bearings |02, |04, |06, |98 and |09, see Fig. 1, which illustrates the' order in which the connecting rods are connected with the crankpin 58. The connecting rods are of equal lengths, and all the rods are connected with' the crankpin 58 of a single throw crankshaft;

The bearings |02 through |08 are respectively provided with needle bearing rollers IIO, the groups being separated by spacing washers |I2 whichalso separate the bearings one from the other.

Each of the cylinders 68 through 16 is provided with a valve chamber H4, these being identical in construction so that the description of one will apply to all. In Fig. 3, the valve chamber ||4 includes a vbody |||i provided with axially aligned intake and exhaust passages I I8 and |26, respectively, communicating with a chamber l|22 having communication with the cylinder S8.

`,Passage |20 communicates with a right-angularpassage |24 for exhausting into a Asuitable conduit |26, and the passage I I8 has communication with a bore |28 communicating with a tube |30, see Fig. 1, communicating with the port |32 in the intake manifold |34, extending circumferentially about the ange 34. Theintake manifold |34 supplies all the cylinders and extends completely about the ange 34, as best illust-rated in Fig. 2. yThe tubes or elbows |30 are secured toV the respective bodies II6 and the intake manifold |34 by bolts |36. In Fig. 3 the cylinder 68 is provided with a relatively heavy flange |30 to which the annular flange |40 of the body |I6 is secured by bolts I42, and the flange |40y is centered with respect to the cylinder by reason of the cylinder flange |44.

Valve chamber cages |46 and 48 are secured to the valve body II6. These valve cages are provided with axially aligned bores |50 and |52, respectively. Bearing faces |54 and, |56 are provided on the cages |46 and |48, respectively, which are respectively pressed into the passages II8 and I 20. Bolts |58 secure the cages to the valve chamber body I I6, as in Fig. 2.

'Ihe stem |60 of the intake valve |62 is slid.;- ably guided in a bushing |64 in the valve cage |50. A compression spring |66 is interposed between the flange |68 on the valve stem |60 and` the wall of the valve cage for yieldingly holding the valve |62 seated on the valve seat insert |1|. The bushing |164 is pressed into a bore |12 in the wall |10. on which the annular face |54 is fashioned.

The valve |62 is threadedly connected with the stemI |60, as at |14, and the valve is provided with aconical bore |=16 for the reception of a split taper key |18A fltting snugly inside the bore and having a flange |80 fitting between the spaced abutments- |82 on a reduced diameter reach ofthe stem |60,- extended into the bore |16. Recesses I 84- are provided in the valve |62- for coaction with a spanner wrench, and the opposite end of the valve stem isv provided with a nut |86 for the receptionof a. wrench to facilitate turning of the valve'on the threads of the valve stem.

'I'he valveY stern |88 of the exhaust, valve- |90 is slidablyguided in ar bushingv |92 secured in the bore |94 in the wall |96 of the valve cage, |48, the bushing |62 being axially aligned.- with they bushing |64:` A- compression spring |98 is interposed between the wall |96 and a flange 200 on the valve stem |88 for yieldingly holding the valve |90 against the valveiseat. insert ,202.` A groove 204 is cut in the valve. stern |88 for the reception of a horseshoe washer 206, which holds the flange 200 in place against theA tension of the` compression spring |98. Two spark plugs 208l a-re threaded into the valve chamber body I I6 for the cham- I ber |22.

Five camshafts 2|0 are employed. These camshafts are equally spaced' circumferentially about the axis of the crankshaft and are identical in construction. Fig. 1 illustrates one of they camshafts 2| 0, which camshaft is supported in bushings 2|2 and 2|4 secured to a lug 2| 6 and the wall 30, respectively, the crankshaft extending beyond the wall for connection with a double chain sprocket 2I8 keyed to the camshaft, as at 220. The sprocket is clamped rmly against a flange 222 on the camshaft through the medium of a nut 224 threadedly connected with the camshaft.

Each camshaft is provided with an intake cam 226 and an exhaust cam 228, respectively, see Fig. 3. In this view, a rocker arm 230 is provided for coaction with the valve stem I 60 and the cam 226. A bolt 232 is receivable in the bore 234 in the rocker arm 230, which bore is located intermediate its ends, and the bolt 232 is supported by a tube 236 bolted to the crank case I0. A split tube 238 has one end embracing the outer end of the tube 236 and its outer end embracing an annular flange 240 on the valve cage |46.

The tube 238 is split longitudinally and its sections 242 are clamped together by bolts 244.

To the outer end of the rocker arm 230 is secured an adjustable screw 246 for engagement with the valve stem |60, and the adjusting screw is secured against accidental rotation by a lock nut 248, in addition to being provided with a screw driver receiving slot 250. Access to the screw 246 may be had by removing the cap 252 boltedtothe valve cage l 46,.

Since the rocker arm 254 coacting with the cam 228 and the exhaust valve stem |88 is identical with the rocker arm 280 and its associated structure, corresponding reference numerals are applied to corresponding parts. The cams 226 and 228 on the respective camshafts 2| 0 are spaced longitudinally on the shafts to accommodate the staggered alignment of the cylindersI 68 on the crank case I0. Thus the cam 228 on the shaft 2|0 to which the cam. 226 is connected for operating the rocker arm 230, is locatedV for actuating the rocker arm 254 associated with the exhaust valve of the cylinder 10. Similarly, the cam 226 on the other camshaft illustrated is arranged to actuate the rocker arm 230- associated with the intake valve of the cylinder 16.

The intake valve- |62 may beremoved by way of the chamber |22. In removing this valve,l a spanner wrench is connected with the Valve and the valve stem turned for threading the stein further into theI valve. This brings thesplit tapered key I 00 suciently. far outside theconical bore |16 to permit the parts, thereof to be removed, after which the stem may be unscrewed from the valve and the. latter removed through the chamber |22, assuming, of course,4 that the valve body ||6 has been removed from the cylinder 68. Y

The valve |90. may be removed with its stem |88 by detaching the horseshoe washer 206 and pushing the valve through the bore IIB.. Removal of the valve cage` |46. permits the valve to be pulled completely outside the valve` body |I6. Thus the valve |90 may be placed in posi-- tion as well as removed without detaching the valve cage |48 from the valve body |I-6.

Each of the. camshafts 2|0 is provided with a double sprocket 2I8 for coaction with. twolchains 256 which are driven by a double sprocket 2-58 secured to a shaft 260 supportedV in bearings- 26,2 and 264 in the wall Sil-and plate 36, respectively, see Fig. l. A double sprocket 266 is keyed to the shaft 260 and is driven by two chainsI 268 passing over the double sprocket, 210. keyed to the crankshaft 20. Becausel of the length of the two chains 256, tightening sprockets 212 are provided.

Chain tightening sprockets 21,2 are located as near as possible to positions on. diametrically op-. posite sides of the axis of the crankshaft 20 so. as not to disturb accu-rate timing of the camshafts through wear of the chains and reduction of slack therein at one point only.

li'igs. 4 and 5 illustrate one of the chain tightening sprockets 2,12. Both, sprockets are mounted in the same manner. I'he wall 30 is provided with a boss 214 having an opening 216 for the reception of a block 218. which fits snugly inside the opening when viewed according to Fig. 5 but which may be adjusted in either direction when viewed according to Fig. 4. A flange 280 is carried by the block to engage the face 282 of the boss 214.

A shaft 284 rotatably supports the sprocket 212 through the medium of the bushing 286 secured in the bore 288 of the sprocket. A threaded shaft 299 is threaded into the bore 292 of the block 218, and the shaft 299 is of reduced diameter with respect to the shaft 284 to provide a shoulder 294 which abuts a spacing washer 296 lying against the wall 39. A flange 298 is formed on the shaft 234 and the latter is provided with a nut 399 to facilitate turning of the shaft. Thus the sprocket is restrained from relative longitudinal movement by reason of the spacing washer 296 and the flange 298 and the block 218 is firmly secured in position when the threaded shaft 299 is turned tightly home, since the block is spaced slightly from the spacing washer 296.

An adjusting screw 392 is threaded into the boss 214 and abuts the block 218. This bolt is made secure against accidental rotation by a lock nut 394 engaging the flange 32. Cover plate 36 is provided with a Work opening 396 axially aligned with the shaft 284, which opening is normally closed by a plate 398 removably secured to the plate 36 by bolts 319.

One of the camshafts 219 of Fig. 1 is provided with a notched end 3l2 to which the oil pump (not shown) may be connected, an opening 3| 4 being provided in the plate 36 to facilitate connection with the end 3l2. The magneto of the engine may be connected with the shaft extension 3|6 coaxial with the axis of the crankshaft 29 and extending through an opening 318 in the plate 36. The shaft 269 is provided with a notched end 329, accessible through an opening 322 in the plate 36 for connection with a tachometer. The carburetor may be attached to the boss 324 on the manifold |34, which boss is provided with a fuel passage 326.

The manifold |34 is provided with a series of ears 338 provided with openings 349 for the reception of bolts which may be employed for securing the engine to an anchor plate.

Without further elaboration, the foregoing will so fully illustrate my invention that others may, by applying current knowledge, readily adapt the same for use under various conditions of service.

I claim:

1. In an engine of the type described, the combination of a valve stem having spaced abutments at one end thereof, a valve head threadedly connected with said stem, and having a conical bore adapted to surround said abutments, and key means engaging said abutments and coacting with the wall of said bore to be clamped into holding engagement with said abutments when the valve is turned relatively to the stem in one direction, to xedly locate the stem and the valve head.

2. In an internal combustion engine, the combination of a valve stern having spaced abutments at one end thereof, a Valve head threadedly connected with said stem, and having a conical bore extending about said abutments, key means in said bore engaging said abutments, and coacting conical faces on said key means and the Wall of said recess, for clamping said key means into holding engagement with said abutments when the valve is turned relatively to said stem in one direction for xe'dly locating the stern and the valve head.

3. In an internal combustion engine, the com bination of a valve stem having spaced abutments at one end thereof, a valve head threadedly connected with said stem, and having a tapered bore Heat dissipating fins 328 are provided on the i bodies H6 of the valve heads H4.

In Fig. 4, an oil sump 339 is bolted to the bottom of the crank case I9 and the wall of the crank case is provided with oil draining openings 332. 'I'he sump is secured to the crank case by bolts 334 and is provided with an opening 336, through the medium of which oil may be drained from the sump in the usual manner.

extending about said abutments, and split keys having formations fitting between said abutments and with tapered faces engaging the Wall of said tapered bore to be clamped between said spaced abutments, and xedly locate the valve head and the valve stem when the valve head is rotated relatively to the stem in one direction.

ANDREW SCOTT. 

